Oh, have fun with your TA chainrings.

Here is the cheapest 70T ring that I've found.
Bikingreen 70T BCD130 Recumbent Chainring CNC 7075 Road Fixie black TT Track | eBay

Both Driveline and Vuelta make a 60T ring for a reasonable price.
mr_ride DRIVELINE 10,11 speed, Road Bike - Racing Chainring 60T BCD 130MM BLACK | eBay

VUELTA SE 110mm 60T SLV | eBay
Vuelta SE Flat 130mm BCD 5-arm Road Chainring | eBay

Here is a mixed 110/130 bcd, 60T
Brompton BCD 110+130 60T Chainring also fits Schlumpf Speed/Mountain Drive (ATS) | eBay

For the TA,
54T
TA Chainring 54 Specialites Criterion Vintage NOS | eBay

57T
RARE VINTAGE TA 57T 3/32nd ALLOY CHAINRING IN GOOD CONDITION FOR MOULTON or TT

You could ask Biking Green if they could make a ring without machining the spider (or machine a custom bolt pattern). I believe the rings are hollowed a bit on the back side... solid might be better.

You may also be able to make a custom spider to fit from your TA to a 110BCD or 130BCD ring.

I have also seen large steel exercise bike chainrings on occasion, often as a solid plate that could be drilled/machined to fit your TA.