It had not been the easiest build-up for the 20-year-old, who has suffered both Covid and shingles, when he rejoined Trinity Racing at the five-day stage race.
But after three decent days, he showed his most encouraging form in the final two stages.
The Ribeauville-Lac Blanc stage featured five mountain passes and, with 4,235m of vertical distance over 161.3km, presented an imposing challenge for the young rider.
Culverwell nevertheless stayed in contact until the last 15km and beat the whole Great Britain U23 team in finishing 57th overall, within 11min. of first place.
‘It was probably my best performance in the mountains, lasting that long,’ he said.
‘It’s something that I have not got much experience in. I am not particularly suited to mountains anyway – not really my forte.’
Feeling surprisingly good the next day, Culverwell finished 72nd and 16sec. off first in the 153.6km Mulhouse-Berrwiller, but he had a taste of so much more.
The Sarnian featured in a big break that lasted, agonisingly, until the last 4km.
‘I think if the break did stick, I had a good chance of winning,’ he added.
‘Out of the eight riders, I would say three were stronger than the rest. Shame we did not stay away, but that’s racing.
‘Pretty happy with how I rode. I think I performed well and I did not get a big result, but I was close in that last day.’
Earlier, his domestique contributions had paid off when Ben Turner placed third in stage two, the Colmar-Altkirch.
Looking ahead, Culverwell is currently training in Spain and preparing for a few full-blast outings in Belgian one-day races.
The first of those takes place on 15 August and is part of his journey towards, hopefully, qualifying for an individual Tour of Britain berth for early September.