Ideally for a single ring set-up it should be a Criterium chainwheel but they seem to be all 50+ teeth. This one's 48 and is about the biggest I'd want to run.
Not to resurrect a zombie thread, but just to clarify Specialites T.A.'s nomenclature, for anyone who stumbles on this later:
"Criterium" is TA's name for a multi-ring setup where the smaller rings are attached by 6 bolts in the 152 BCD position. The smallest secondary ring is 43T.
"Randonneur" is TA's name for a multi-ring setup where the smaller rings are attached by 6 bolts in the 116 BCD position. The smallest secondary ring is 36T.
"Cyclotouriste" is TA's name for a multi-ring setup where the smaller rings are attached by 6 bolts in the 80 BCD position. The smallest secondary ring is 26T.
But the BCD of the smaller rings doesn't tell you much about the attachment to the crankarms. The outer rings for all three formats attach to the driveside crankarm through 5 bolts at 50.4 BCD. Effectively, the outer ring is the spider attaching the secondary rings to the crankarm. The 50.4 "5-pin" format has been used since the 1920s, both by British and European manufacturers, with both cottered and cotterless cranksets. The best-known modern cotterless/square-taper aluminum cranksets are the Specialites T.A. Pro V (available off and on since 1963) and the Stronglight 49 (variations available from 1936 through the 1970s). Other cotterless 50.4 cranks include: Nervar 631, Sugino Super Maxy Triple and PX, Shimano FC-DE20/30, TA knockoffs by Velo Orange and Electra; outer chainrings may be freely swapped between these manufacturers - but
not the 5-pin Zeus Competition, which has a 50 BCD crankarm attachment incompatible with rings from all the other manufacturers.
The inner chainrings for these manufacturers each tend to use their own unique BCD for inner rings: 80, 116 or 152 for TA Pro V, 122 BCD for Stronglight 49, 128 BCD for Nervar, 143 BCD Lambert outer hole, 157 BCD Nervar/Solida/Simplex/Zeus etc. But the combination of crankarms from one manufacturer with chainrings from another is very common in 50.4 World. A common practice in 50s European racing was to use the Stronglight 49 with TA chainrings, either attached directly from the outer chainring/spider, or through TA's 6-arm adapters to their 152 "criterium" or 116 "randonneur" chainrings. This was before TA started producing cranks in 1962. The use of large-BCD chainrings with 5-pin adapters made it quick to change chainrings without extracting the crank - very handy for track racers.
Lambert/Viscount's rings, in both their TA-knockoff version and the porthole version, will attach to TA crankarms. The inner holes will attach to 80 BCD TA "cyclotouriste" chainrings - the most common 50.4 rings around. The 147 BCD ring is unique to Lambert; I suspect that the only rings that ever fit that were the ones Lambert originally had made. Probably not wise to tie up a lot of money in those, or energy tracking them down.
Although I own several sets of TA Pro V and Stronglight 49 cranksets, I tend to restrict them to special use bicycles, particularly lightweight French racers. This is because both the TA and the Stronglight use uniquely-sized crank extractors: 23mm for TA, 23.35mm for Stronglight. Instead, for my daily rider/touring bike (a heavily modified Raleigh International), I use Nervar 631 - also French, also 5-pin 50.4, but it uses a common Campagnolo/Shimano 22mm extractor. If I'm out in the wild somewhere and I need to service a bottom bracket or swap a chainring, I can go into a shop and ask - I don't have to carry a special extractor with me.
I use TA chainrings exclusively, regardless of which crankarms I'm using. For my daily riders, I use 80 BCD "cyclotouriste" rings (range from 26-64T; my normal range is from 26-50T). For 50s-early 60s go-fast setups, I use 152 BCD rings with a TA 50.4-to-152 "professionel" adapter.
Single 50.4 setups are usually used either for track, for specialty hour-record bikes (TA made standard 50.4 rings up to 64T, and there are reports that they made larger rings up to 100T), or as timing rings for their very popular Pro V tandem cranksets. The track rings are almost always 1/8" thick; the non-track rings are normally 3/32". Bit if you have an outer ring that has the toothcount you want, you can use it as a single ring and ignore the inner-ring holes.
The key resource for Specialites T.A. information is Joel Metz's
BlackbirdSF - well worth a look for some nifty engineering. If I had a bike with the exquisite TA pedals, TA "criterium" cottered crankset and a TA headset, I'd die a happy man. One pedal+"criterium" driveside arm down...
Bloody Google! 
