Both won their early December trials, in Entriviere's case she hacked up to win at Rotorua on the 13th.
Bosson rode her that day as he did in two of her early trials but tomorrow will be his first race ride on the flyer and he has grown in confidence every time he has sat on Entriviere in the last fortnight.
"Her trial was good and then she galloped in between races at Matamata and that was even better," Bosson told the Herald.
"And she has come on even more since then. I rode her in track work this week and she is ready to go. Bang on.
"She is going to need to be as it is a very good field and we know how good Levante and some of the others are so she is going to need to be ready.
"But if she can begin well and settle handy then she is the one to beat for mine."
While any unlikely rain would aid Entriviere, who relishes getting her toe in to the ground, Bosson says the Ellerslie track had good cushion in it on Boxing Day and he isn't concerned it will be too firm for his mare if the rain doesn't come.
Entriviere won twice over 1200m on Dead4 tracks at Ellerslie this time last year, recording times in the fast 1:09 range with 33-second last 600m sectionals.
If she can settle in front of Levante, which on their past racing patterns would seem likely, and perform to her best she is clearly the one to beat.
The Railway only has nine starters but it is one of the deeper major sprint races held in New Zealand in recent years, with all the starters either proven Group 1 performers or in-form and racing like they could reach that level.
In fields of that quality, luck and field position tend to play a role and a key factor for those who get back in the second half of the field will be whether the likely leaders of Babylon Berlin, Rose N Power and Packing Rockstar try to ease the mid-race tempo once they have sorted themselves out, or whether they keep running hard and the swoopers come into play late.
Bosson also warns one-start juvenile I Choose You is a class act and can test Karaka Million favourite Wolverine in the $120,000 Eclipse Stakes tomorrow.
"She went to Ellerslie for a track gallop two weeks ago and handled it really well. Again it is a good field but I like this filly."