A FIDE 1400 converts to US Chess 1120 (-1073 + FIDE*1.5667) while an 1800 converts to a US Chess 1747. You may want to change the US Chess rating band you are comparing to.
PS 1894 FIDE converts to 1894 US Chess. Under that the US Chess rating is lower than the equivalent FIDE rating. Above that the US Chess rating is higher.
Good idea to add the formula, too – key is to get anyone who is 1400-1799 FIDE
Looking back at my old script.
Get all NC Reg Rat – current member or “played” in last year (more likely to play)
Add Fide Classical Rating for anyone in 1
Flag for 1400-1799 FIDE we would count these no matter what USCF is as they are key to getting a newbie a rating
Flag for USCF 1400-1799 I removed folks outside this range unless they were in 3 – probably better to not bother with the lower bound and make the upper bound 1747. I thought most of the 1700ish FIDE were 1800-2000 USCF
I wanted to second your notion that something less than Senior TD be required for FIDE NA. Here in SC, we have very few tournaments that qualify for Sr. TD credit and we are hesitant to convert the ones that draw 50+ players to FIDE even though we have the arbiters. Because only FIDE-credentialed TDs can be on the masthead for a tournament, converting them would make it nearly impossible for future TDs nearby to gain experience to become Senior TDs and subsequently National Arbiters. It’s essentially climbing a ladder and pulling it up behind you currently.
This part is problematic and something we also noticed locally. Frankly we use our scholastic events as our non-FIDE trainer events for those credits.
I mean, having a pathway for Local TDs to become NAs - but not Chief Arbiter NAs - would at least partially solve the issue of cannibalizing the pathway to Senior through running FIDE events.
Maybe a good intermediate step would be to allow Local TDs who have completed all of their 30.a3 requirements (since these can theoretically be accomplished by substitution) be allowed to sit for FIDE NA exam. Simplest revision path.